Pavement joint sealing device



United States Patent [72] Inventor John F. Feister, Silver Lake, Ohio (3008 Silver Lake Blvd., Cuhahoga Falls, Ohio44224) [21] App]. No. 730,077 {22] Filed May 17,1968 [45} Patented Sept.8, 1970 [54] PAVEMENT JOINT SEALING DEVICE 12 Claims, 8 Drawing Figs.

[52] U.S.Cl... 94/18 [51] Int. Cl E01c 11/10 [50] Field ol'Search 52/396;

[56] References Cited UNITED STATES PATENTS 2,135,048 11/1938 Giffin 94/18 2,246,903 6/1941 Spears 94/18 2,315,588 4/1943 Briekman... 94/18 2,867,160 1/1959 Wangerow 94/18 3,068,763 12/1962 Harza 94/18 3,124,047 3/1964 Graham... 94/18 3,172,237 3/1965 Bradley 94/18X 3,368,464 2/1968 Thorp 94/18 OTHER REFERENCES Rubber Journal January 1965 page 68 (Scientific Library) Primary Examiner-Jacob L. Naekenol'f Armrney- McNenny, Farrington, Pearne and Gordon ABSTRACT: A seal for contraction joints between concrete pavement slabs in highways and the like, comprising an inverted, generally U-shaped, elastomerie sealing strip seated in a shouldered groove between the slabs with a strand of wire, plastic, or the like extending through each leg of the strip and secured under tension to the respective slab to hold the legs of the strip pressed downwardly against the shoulders and laterally against the sides of the groove. The elasticity of the strip also presses the legs apart and against the sides of the groove. The sealing strip may be an elongated strip folded about its centerline and the legs may be initially held together to facilitate installation by a weak adhesive which is broken apart when the strands are tensioned. The outer surfaces of the legs may also carry an adhesive to assist in sealing against the sides of the grooves. When used with crowned highway slabs, the crown cooperates with the tensioned strands to hold the sealing strip down in the groove throughout its length.

Patented Sept. 8, 1970 3,527,147

Sheet of 2 INVENTOR.

JOA/M, F. A575 761? BY MNA/A/K ICAIQIQ/A/CTOM AKA/Qua. g aaeom/ Patented Sept. 8, 1970 3,527,147

Sheet 2 of 2 lPllWlEh/IENT JOINT SEALING DEVICE BACKGROUND OF THE INVENTION This invention relates generally to sealing devices for expansion and contraction joints, and more particularly to a novel and improved preformed sealing device having separable leg portions engaging the opposite sides of the joint and held in place by tensioned strands of metal wire, plastic, or the like.

In modern highway construction, the pavement material, such as concrete, is poured in a continuous strip. Since the concrete shrinks during curing, it is subjected to internal tensile stresses which would cause irregular transverse cracking randomly throughout the highway if they were not relieved. To avoid such uncontrolled random cracking, transverse contraction joints are sawed in the concrete at regularly spaced intervals as soon as the concrete has hardened enough to support the weight of sawing equipment. The contraction joints are not sawed completely through the concrete, but are sawed to a depth of only about one-sixth of the pavement thickness. This, however, is sufficient to weaken the concrete strip at the sawed slots so that further contraction of the concrete upon curing will crack the concrete through the rest ofits thickness at the sawed slots.

It has been a long-standing problem to attempt to maintain these transverse joints sealed to prevent infiltration of both solid materials and surface water. As the ambient air temperature drops, the pavement further contracts, causing the joints to open. When dirt, pebbles, or other incompressible material enters the opened joints, such material prevents the joints from closing when the ambient temperature subsequently rises and expansion occurs. This results in high compressive stresses, which cause severe spalling and scaling of the pavement surface, and also cause the pavement to grow in length with consequent danger of buckling or pushing over bridge abutmcnts adjacent the ends of the concrete strip. Furthermore, surface water entering the joint is pumped out and then sucked back in when a heavy vehicle rolls over the joint, thereby eroding the subsurface of the highway and pumping dirt into the joint.

An asphalt or similar sealing material has been heretofore commonly employed in an effort to seal these joints in highways, Suchtrnaterials, however, are squeezed out of the joints in warm weather as the pavement expands, causing bumps which adversely affect the riding qualities of the finished highway. Furthermore, such materials do not adhere to the opposed surfaces ofthe joint with sufficient force to be pulled back into the joint when the pavement again contracts, so that foreign materials enter the joints wherever the asphalt has not been pressed back. This results in joints sealed with such materials requiring frequent maintenance.

in unsuccessful efforts to solve the problem, various preformed sealing devices have been proposed and tried. Devices to be supported on forms while the concrete is poured about them and allowed to harden cannot be used when the pavement is poured in a continuous strip. Hollow rubber strips intended to press against the sides of the grooves at all times are very difficult to install, since the sawed grooves are usually near their minimum width at the time the strips must be in stalled. in addition, the pumping action of the slabs under heavy traffic acts to work and force the strips upwardly out of the joints.

SUMMARY OF THE INVENTION The expansible seal of the present invention includes a strip of butyl rubber or other suitable material having separable leg portions to engage the opposite sides of the joint to be sealed. Tension strands, which may be of nylon, polyester, metal wire, or other suitable material, are secured under tension to the concrete on opposite sides of the joint, with each strand firmly holding one of the leg portions of the seal against its side of the joint.

A further feature of the invention is the forming of a shouldered groove at the joint to receive an expansible seal, the tension strands being secured to the opposite sides of the pavement slabs and arranged at an angle so as to press the legs of the seal downwardly against the shoulders of the groove, as well as laterally against the sides. This feature of the invention saves time and expense, since the major part of the depth of the groove required to insure cracking through the slab during contraction is sawed much narrower than the portion wide enough to receive the seal.

Still another feature of the invention is the cooperation of the tensioned strands with a crown in the highway to hold the sealing strip down in the shouldered groove along substantially the entire length ofthe groove.

In a specific embodiment, the seal is a flat strip of butyl rubber with a tension strand enclosed or embedded therein adjacent each lateral edge. Prior to installation, the strip is folded substantially about its centerline to form an inverted, U-shaped sealing strip having two separable leg portions and a top portion. A weak adhesive may be provided along the inner surfaces of the legs to hold the strip in this folded position prior to installation in the joint, The sealing strip is then installed in the joint, so that the leg portions resiliently engage the opposed surfaces of the joint and the top portion bridges the varying width of the joint. A lubricant-adhesive may be provided between the legs ofthe strip and the opposed walls of the joint to aid in installation of the strip and to further secure the strip within the joint.

Although the present invention is described primarily in connection with expansion and contraction joints in highways, it can be appreciated that it may also be incorporated in other structures, such as dams, bridges, and the like, without departing from the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS These and other advantages of the invention will more readily become apparent to those skilled in the art upon a full and comprehensive understanding of the preferred embodiments of the invention as shown in the accompanying drawings, wherein:

FIG. 1 is a perspective view of a portion of a longitudinally extending highway having transverse contraction joints and incorporating the present invention;

FIG. 2 is an enlarged, broken, perspective view of the sealing strip used to seal the transverse contraction joints in the highway shown in FIG. 1;

FIG. 3 is an enlarged side elevation in section of the sealing strip shown in FIG. 2;

FIG. 4 is an enlarged, fragmentary side elevation of one of the contraction joints in the highway shown in FIG. 1 prior to installation ofthe sealing device;

FIG. 5 is an enlarged, fragmentary side elevation of one of the contraction joints in FIG. 1, with the sealing device in position;

FIG. 6 is an enlarged, fragmentary side elevation of a contraction joint, with the sealing device installed according to one preferred embodiment of the invention and with the contraction joint opened;

FIG. 7 is an enlarged, fragmentary perspective view of a portion of the highway shown in FIG. 1, with the strands of the sealing device held in position according to another preferred embodiment of the invention; and

FIG. 8 is a perspective view of the means by which the strands are secured in place in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings in greater detail, FIG. I shows a crowned, continuously placed concrete highway designated generally by reference numeral 11. After the concrete has been placed, but prior to full curing and hardening, the transverse shouldered grooves 12, 13, and 14 are sawed in the concrete to separate it into the adjacent slabs l6 and 17. The shouldered groove 13 includes a relatively wide slot and a narrower but deeper slot 21, the junction of these slots defining a shoulder 22. The wide slot 20 may be sawed on the order of one-quarter inch wide and one-half inch deep. The narrow slot 21 may have a width on the order of oneeighth inch and a depth of about one-sixth of the thickness of the concrete slab, or about one and one-half inches for a teninch thick slab. The shouldered groove 13 is also provided with acute angles at 24 and 25 for reasons which wil hereinafter become more readily apparent.

After the shouldered grooves are sawed in the concrete, further curing takes place. Since the concrete shrinks upon further curing, it becomes subjected to increased tensile stresses. When these stresses become great enough, the concrete cracks through its entire thickness at its weakest points, which are the locations of these sawed grooves. The width of the joint formed at each of these sawed grooves, of course, varies with changes in the ambient temperature. For example, if the joints are spaced to form one hundred foot long slabs, the width of each joint would vary on the order of one-half inch over a temperature range of 80 Farenheit degrees.

If the varying width contraction joints in the highway 11 were not provided with a sealing device, materials such as dirt and stones could enter in cooler weather when the pavement slabs contract and the joints are opened. Then, in warmer weather when the pavement expands to close the joints, the joints would not be able to close and the highway would gradually grow longer. Furthermore, the absence of a sealing device would permit water to flow into the joints, which would erode the subbase of the highway. Additionally, such water could accumulate in the joint and under the highway and cause adverse effects upon freezing.

In order to overcome these difficulties, a pavement joint sealing device is installed in each of the shouldered grooves. The sealing device according to the preferred embodiment of the invention is of extremely simple construction and includes a resilient, elastomeric sealing strip 29 which is preferably of butyl rubber, although it may, of course, be of any other suitable material. The strip 29, according to the preferred embodiment, includes an enlarged central portion for added resistance to abrasion and enlarged end portions for improved sealing with the shouldered groove, although it may be of various cross sections, such as U-shaped or even substantially flat and uniform. Two tension strands 30 and 31 are embedded within the strip 29 substantially adjacent its lateral edges 32 and 33, respectively. The strands 30 and 31 according to the preferred embodiment are of stainless steel wire, since it will not rust. Furthermore, the high yield strength and high tensile strength of stainless steel make it well suited for this purpose, in which it is under tension at all times. The use of polyester or nylon cords is also contemplated, and, of course, any suitable material, whether woven or single strand, reinforced or nonreinforced, may be used. It may be appreciated that the strip 29 must be flexible enough to bend without cracking even in extremely cold weather, and should not deteriorate substantially or lose its resilience after prolonged exposure to the elements. The strip should also have good resistance to petroleum products and, furthermore, should exhibit good wear resistance to abrasive materials, such as sand and gravel. 1n the preferred method of making the invention, the butyl rubber sealing strip 29 is continuously extruded with the strands enclosed or embedded therein.

Prior to installation in the joint 13, the sealing strip 29 is folded substantially about its centerline 36 to form an inverted, U-shaped structure having separable leg portions 37 and 38 adapted to resiliently engage the opposed surfaces 39 and 40 respectively of the shouldered groove 13, and a top portion 41 adapted to bridge the varying width of the joint. A relatively weak, pressure-sensitive adhesive is applied to the inner surface of the legs 37 and 38 at 42 and 43 to hold the sealing strip in its folder position and facilitate installation. Although in the preferred embodiment, the weak adhesive is applied in two continuous strips 42 and 43, it could, of course,

- be applied to only one leg portion, or it could be applied in patches rather than as continuous strips.

With the sealing strip 29 held in this folded position, it may be easily inserted into the shouldered groove 13. Since the joint sealing devices must be installed before the highway is opened to public traffic, and since the concrete is normally placed when the weather is warm, the contraction joint will normally be closed when the seal is installed. Prior art sealing devices, particularly those with internal support elements, are extremely difficult to install when the contraction joint is closed, since they must be compressed to a fraction of their natural width prior to insertion in the closed joint. However, since the folded strip 29 has a relatively thin wall thickness and no internal support elements, it may be inserted into the closed contraction joint very quickly and easily even by a single worker and without the use of force-applying tools. Additionally, the invention permits narrowing the sawed groove at a further saving of time and expense.

The opposed surfaces 39 and 40 of the joint 13 may be coated with a lubricant-adhesive at 44 and 45 prior to installation of the seal. This lubricant-adhesive serves as a further aid to installation, aids in securing the sealing strip to the surfaces 39 and 40, and may fill the pores in the concrete to effect a better seal. t

After the sealing strip has been inserted in the groove 13, the strand 30 is secured under tension to its adjacent slab 16, and the strand 31 is similarly secured under tension to its adjacent slab 17. The application of a force in the lateral direction to the ends of the strands 30 and 31 breaks the bond of the pressure-sensitive adhesive and causes the sealing strip 29 to spring open so that the leg portions 37 and 38 engage the opposed surfaces 39 and 40 respectively with a resilient force. The top portion 41 of the strip 29 then bridges the varying distance between the adjacent slabs 16 and 17 to seal the joint against infiltration of unwanted materials. The tension applied to the strands 30 and 31 may also break to some extent any adhesion that might have occurred between them and the legs of the sealing strip, so that tension is applied throughout the length without distorting the sealing strip.

An engagement means best shown in FIGS. 7 and 8 may be employed to secure the ends of the strands 30 and 31 to their respective adjacent pavement slabs 16 and 17. An L-shaped bracket 46 cooperates with a similar bracket on the other side of the slab 16 to secure the strand 30 thereto. In a similar manner, the bracket 47 cooperates to secure the strand 31 to the slab 17. One arm 49 of the bracket 46 extends beneath the lower surface 50 of the slab 16, while the other arm 51 extends along the side wall 52 of the slab. The arm 49 is provided with a plurality of protuberances 53 which engage the rough lower surface 50 of the slab to hold the bracket 46 in position when tension is applied to the strand 30. The brackets may be of aluminum or other corrosion-resistant material to insure a long, maintenance-free life of the sealing device. Alternatively, the tension strands 30 and 31 may be secured to their adjacent slabs by studs 56 and 57, respectively, as shown in FIG. 6. The studs may be ram-set into the pavement slabs after hardening, or they may be positioned prior to hardening.

The strands 30 and 31 may be secured to the brackets 0r studs with the aid of a conventional tensioning device or wire stretcher to assure that each strand is installed under the proper tension. It has been found that a force of ten to fifteen pounds forcing the seal into the shouldered groove is sufficient to insure that the strip is properly locked in position. The brackets or studs are arranged so that the tension strands 30 and 31 extend at angles 59 and 60 of about 45 each, measured from the horizontal, to press the strip downwardly against the shoulders and laterally against the opposed surfaces of the groove. The acute angles at 24 and 25 then aid in properly positioning the leg portions 37 and 38 against the opposed surfaces 39 and 40 of the joint. After the strands have been secured to their adjacent pavement slabs, any suitable seals for the ends of the joints may be installed if desired and the shoulders of the highway may then be constructed to complete the highway.

The crowned surface of the highway 11 may be either pointed or rounded. According to modern highway construction practices, if the pavement is placed in single lanes, the crown is generally pointed, while if both lanes are finished in one operation, the crown is generally rounded. When the pavement It is provided with a crowned surface, it will be appreciated that the tension strands 30 and 31 apply a greater downward force for a given tension at intermediate points in the length ofthe strip. This helps insure that the sealing strip is positively interlocked with the shouldered groove 13 along its entire length and cannot vibrate loose or work out of the joint with the passage of motor vehicles thereover.

With the side walls 37 and 38 of the seal mechanically interlocked, as well as resiliently interlocked with their adjacent slabs by means of the tension strands 30 and 31, it can be appreciated that even substantial relative movement between the slabs will not cause the sealing device to be loosened or otherwise adversely affected.

Although a preferred embodiment oi'the invention has been shown and described in detail herein, it is recognized that various modifications and rearrangements will readily become apparent to those skilled in the art upon a full and comprehensive understanding of this invention, and may be resorted to without departing from the scope of the invention as defined in the following claims.

ll claim:

1. in a pavement having ajoint for accommodating contraction and expansion comprising a shouldered groove extending across the pavement from one side thereof to the other, :1 flexible sealing strip bent in the shape of an inverted U inserted in said groove with its longitudinal edges resting on said shoul' ders, and tension strands in the longitudinal edges of said strip extending beyond the opposite ends of said strip and anchored to the sides of said pavement.

2, A seating strip as set forth in claim 1, wherein said ends of said tension strands are secured to said sides of said pavement by two armed brackets having one arm extending under said pavement and the other arm reaching along the lateral surface ofsaid pavement and engaging said strand. A

3. A sealing strip as set forth in claim 1, wherein said ends of said tension strands are secured to said sides of said pavement by studs embedded in the lateral surface of said pavement.

d. in a pavement having a joint for accommodating contrac tion and expansion comprising a groove extending across the pavement from one side thereof to the other, an elongated flexible sealing strip inserted in said groove, said strip having side portions engaging opposite walls of said groove and a top portion bridging said groove, a tension strand extending longitudinally along said strip and beyond the opposite ends thereof, the ends of said strand being secured under tension to press one of said side portions of said strip against the adjacent wall of said groove, and the other of said side portions of said strip being held in sealing engagement against theopposite wall of said groove.

5. A sealing strip as set forth in claim 4 wherein said groove is a shouldered groove, and the ends of said tension strand are arranged at an angle so as to press said one side portion downwardly against the adjacent shoulder of said shouldered groove and also laterally against the adjacent side of said shouldered groove.

6. A sealing strip as set forth in claim 5, wherein said pavement is a crowned highway, and said crown cooperates with said tension strand to press said one side wall portion downwardly against said adjacent shoulder along substantially the entire length of saidjoint.

7. A sealing strip as set forth in claim 4, wherein said tension strand is ofa different material than said sealing strip.

8. A sealing strip as set forth in claim 4, wherein said ends of said tension strand are secured under tension to opposite sides of said pavement. I

9. A sealing strip as set forth in claim 4, wherein said portions of said tension strand extending beyond said opposite ends of said strip are substantially exposed at opposite sides of said pavement.

10. In a pavement having a joint for accommodating contraction and expansion comprising a shouldered groove extending across the pavement, an elongated flexible sealing strip inserted in said groove and engaging said shoulders, said strip having side wall portions engaging the opposite sides of said groove and a top wall portion bridging said groove, two tension strands enclosed within said strip and extending through said strip and beyond the opposite ends thereof, the ends of one of said strands being anchored to said pavement on one side of said joint and holding one side wall portion of said strip against the adjacent side of said groove, the ends of the other of said strands being anchored to said pavement on the other side of said joint and holding the other side wall portion against the other side of said groove.

11. A sealing member for insertion in a joint for accommodating contraction and expansion of a pavement comprising an elongated resilient strip bent transversely to bring its longitudinal edges together, pressure sensitive adhesive between said longitudinal edges releasably holding the same together, and tension strands in the longitudinal edges of said strip extending through the full length of said strip and projecting beyond the opposite ends thereof.

12. in a pavement having a joint for accommodating contraction and expansion comprising a groove extending across the pavement from one side thereof to the other, an elongated flexible sealing strip inserted in said groove, said strip having side portions engaging opposite walls of said groove and a top portion bridging said groove, a tension strand extending longitudinally through said strip, and means for anchoring the ends of said strand to stress said tension strand in tension in a direction substantially parallel to the longitudinal axis of said strip, each of said side portions of said strip being held in sealing engagement with its adjacent wall of said groove. 

